[jnull]

Hello,
I am modelling a furnace with two coal inlets as well as an inlet for CaCO3 particles. Everything has been running as expected for 45000+ iterations, and was just a matter of waiting for the energy to balance (it is a very large domain). Unfortunately, the combustion flame suddenly went out and has since just been a heat transfer problem with the system approaching equilibrium based on temperature of the inlets. I have found what I think to be the problem is that looking at mass fraction of O2 contours, the environment has been choked out so there is no oxygen to aid combustion. I have a velocity inlet with .21 (mole fraction) O2 air coming in near the coal inlets.
I am running the species transport model (finite rate/eddy dissipation), with the coal being a 2 step volumetric reaction. I have tried both increasing and decreasing dpm injection frequency, adjusting the vaporization temperature of the coal particles, as well as turning dpm off for a prolonged period of time (1000 iterations) to try and let the oxygen replenish without any attempts of combustion but this did not help. Does anyone have any ideas on why this occurred and/or methods of fixing it?

Thank you